How to check is a string or number

Question

I have an array ["abc", "94761178","790"]

I want to iterate each and check is a String or an Integer?

How to check it ?

How to convert "123" to integer 123

Answer 1

Here is a small Swift version using String extension :

Swift 3/Swift 4 :

extension String  {     var isNumber: Bool {         return !isEmpty && rangeOfCharacter(from: CharacterSet.decimalDigits.inverted) == nil     } } 

Swift 2 :

   extension String  {         var isNumber : Bool {             get{                 return !self.isEmpty && self.rangeOfCharacterFromSet(NSCharacterSet.decimalDigitCharacterSet().invertedSet) == nil             }         }    } 

Answer 2

Edit Swift 2.2:

In swift 2.2 use Int(yourArray[1])

var yourArray = ["abc", "94761178","790"] var num = Int(yourArray[1]) if num != nil {  println("Valid Integer") } else {  println("Not Valid Integer") } 

It will show you that string is valid integer and num contains valid Int.You can do your calculation with num.

From docs:

If the string represents an integer that fits into an Int, returns the corresponding integer.This accepts strings that match the regular expression "[-+]?[0-9]+" only.